Read original post at Johan Bjarneryd's Blog
Quite often you would like to have a Collection in your view model that supports multiple types that derives from the same base type. Along with the different subclasses, you might want different data templates in your view, one for each type. Microsoft Prism can help you do this in an easy way and automatically select correct template for each type. This post will show how to do it on Windows Phone and you can also download the source code for the demo project (Windows Phone 7.1 for compatability) at the bottom of the page.